Protective effects of Dunaliella salina – a carotenoids-rich alga – against ultraviolet B-induced corneal oxidative damage in mice

PURPOSE Ultraviolet B (UVB) radiation from sunlight is known to be a risk factor for human corneal damage. The purpose of this study was to investigate the protective effects of Dunaliella salina (D. salina) on UVB radiation-induced corneal oxidative damage in male imprinting control region (ICR) mice. METHODS Corneal oxidative damage was induced by exposure to UVB radiation at 560 μW/cm(2). Animals were orally administered (gavage) D. salina at doses of 0, 123, and 615 mg/kg bodyweight/day for eight days. Corneal surface damages were graded according to smoothness and the extent of lissamine green staining. Corneal glutathione (GSH) and malondialdehyde (MDA) levels, as well as the activities of superoxide dismutase (SOD), catalase, glutathione peroxidase (GSH-Px), and glutathione reductase (GSH-Rd) in cornea were measured to monitor corneal injury. RESULTS UVB irradiation caused significant damage to the corneas, including apparent corneal ulcer and severe epithelial exfoliation, leading to decrease in the activities of SOD, catalase, GSH-Px, GSH-Rd, and GSH content in cornea, whereas there was increased corneal MDA content as compared with the control group. Treatment with D. salina could significantly (p<0.05) ameliorate corneal damage and increase the activities of SOD, catalase, GSH-Px, GSH-Rd, and GSH content, and decrease the MDA content in corneas when compared with the UVB-treated group. CONCLUSIONS The studies demonstrate that D. salina exhibits potent protective effects on UVB radiation-induced corneal oxidative damage in mice, likely due to both the increase of antioxidant enzyme activity and the inhibition of lipid peroxidation.